1. Field of the Invention
The present invention relates generally to electrochromic devices and, in one particular aspect, to an electrochromic device utilizing an organic electrochromic material on one electrode and an inorganic electrochromic material on another electrode.
2. Description of the Current Technology
Various techniques are currently utilized in order to increase the energy efficiency of architectural windows, e.g., to control the amount of solar radiation transmitted through the windows. One technique is to apply a solar control coating onto the window to block certain ranges of electromagnetic radiation. Such conventional coatings are designed to transmit a high percentage of visible light but to block ranges in the solar infrared and/or solar ultraviolet ranges to reduce the heat load in the interior of the building. A drawback to these systems is that they are non-dynamic. That is, they do not have the capacity to vary the solar energy transmittance through the window. For example, while it may be desirable to block or reduce the transmission of solar energy through the window during the hot summer months to decrease the interior heat load, it may be desirable to increase the solar energy transmittance through the window during the winter months to increase the interior heat load.
One technique to solve this problem has been the use of electrochromic technology. Conventional electrochromic windows use an electrochromic medium that changes color upon the application of an electrical potential. These conventional electrochromic windows typically darken upon the application of an electrical potential to reduce transmittance and lighten upon the removal of the electrical potential. Such electrochromic devices are finding more acceptance in various areas of commercial activity, such as architectural windows and vehicle windows. However, there are problems associated with these conventional electrochromic devices. For example, these devices are typically expensive to produce and install. Also, the components of these devices can degrade over time due to heat, exposure to solar radiation, or repeated cycling from dark to light, making the device slower to recover to the lightened state.
Therefore, it would be desirable to provide an electrochromic device having advantages over electrochromic devices currently available.